Steam iron water valve wick structure



March 3, 1970 w. JDAvmsou 3,497,975

' STEAM IRON WATERYALVE WICK STRUCTURE Filed m 24. 1968 v 1 32 i alrrl i lIIIIIII/A Q! X a /a Z Fig. 2

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; Inventor: F 50 4 wllllam E. Davldsan Attorney I U.S. Cl. 3877.83

United States Patent 3,497,976 STEAM IRON WATER VALVE WICK STRUCTURE William E. Davidson, Ontario, Califl, assignor to General Electric Company, a corporation of New York Filed June 24, 1968, Ser. No. 739,535 Int. Cl. D06f 7.5/06, 75/18 8 Claims ABSTRACT OF THE DISCLOSURE The invention discloses a steam iron water valve structure with improved wicking means to provide for continuous and regular dripping of water into a steam generating chamber. The wicking structure is of predetermined dimensions, simple, easy to assemble, and of entirely or partially low cost sheet metal construction.

BACKGROUND OF THE INVENTION Field of the invention The invention herein pertains to a steam iron and, more particularly, to a feed water valve structure between the water tank and steam generator that employs an improved simplified wicking structure to ensure the continuous regular feed of water.

Description of the prior art With the advent of irons using water for either steam or spray purposes or both, it is customary to provide a water tank in the iron above the soleplate and to use water valve structure for controlled water drippage into a steam generator where it is evaporated and directed out steam holes in the soleplate to steam the article. Additionally, spray attachments have been added to such irons to supply a fine spray, either manually or power operated, from the water tank to spray onto the garment. Steam irons are generally designed to use distilled water because of the finess of various water passages and orifices which are subject to clogging due to mineral deposits in normal tap water. Because of this fineness, it is sometimes difficult for the water to continuously drip to generate steam because of the surface tension that inherently prevents the passage of water through small passages. It has been customary to provide some wicking structure in order to ensure the flow of water through the metering orifice to the steam boiler. A typical such structure is shown in U.S. Patent 3,161,971 of common assignment which employs a control water valve orifice followed by a downwardly directed cone. Because of surface tension of the water, it tends to form a droplet on the lower side of the orifice that may hang, thus blocking flow through the orifice. A means must be provided to break this surface tension and wick the water downwardly into the steam boiler. This may take the form of the downwardly directed cone or diverging nozzle-like passage, as shown in the patent, which breaks the surface tension and spreads the water so it flows through the orifice with a constant drip into the steam boiler. Generally such valve orifice structure, while it functions satisfactorily has employed a solid valve body as shown which is formed on a screw machine or with the subsequent machining operations to form a finished valve.

SUMMARY OF THE INVENTION Briefly described, the present invention is directed to a steam iron that has an enclosed water tank and a fill opening with a heated soleplate at the bottom onto which water is dripped through an orifice to generate steam in a boiler in the soleplate. An on-otf water valve structure is provided to stop and start the water flow from the bottom 3,497,976 Patented Mar. 3, 1970 of the tank to the soleplate and the particular water valve structure includes improved wicking means that comprises a cylindrical duct with an enlarged upper portion necking down to a reduced diameter lower portion, the duct being connected to direct water from the tank to the soleplate. A preferably conical orifice member is disposed within the upper portion of the duct either integrally therewith or separate, and has an orifice at its lower apex. A valve means is provided to open and close the orifice for controlling water flow and a separate wicking means in the form of a disk-shaped washer plate has a central aperture closely surrounding the orifice. The wicking plate is preferably provided at right angles to the direction of water flow and in the top of the lower duct portion to extend radially from the orifice to the duct with all parts being disposed in predetermined spaced relation. This plate provides a wettable surface between the orifice and duct so that water drops through the orifice are directed along the wicking means to the duct and then to the soleplate. The washer plate, orifice, and the top of the lower portion of the duct are all substantially in the same plane and all parts can be simple sheet metal parts for easy and inexpensive assembly.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevational view, partially in section and broken away, showing general parts of an iron and illustrating the improved water valve wicking structure of the invention; and

FIG. 2 is an enlarged partial cross-sectional view of the wicking water valve structure shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1 there is shown an electric steam iron that may include a spray attachment if desired although the invention is applicable to a steam iron without the spray attachment. The iron includes a soleplate 10 having a plurality of steam ports 12 and an outer shell 14 which is connected in any suitable manner to handle 16 all in known fashion. In accordance with conventional practice, soleplate 10 may be cast from a suitable material such as aluminum with an electrical heating element 18 cast in position. This heating element preferably is of the sheath type and, with the electrical resistance element, extends through an outer tubular protective sheath with the heating element separated from the outer sheath by an insulating compound resistant to heat such a granulated and compressed magnesium oxide. The heating element generally extends in a loop beginning at the rear of the iron and along one side to the forward end then rearwardly along the other side. Thus, substantially uniform heat distribution is provided when the iron is plugged in and activated.

The iron includes means for generating steam by providing a water tank 20 which may have vertical forward portion 22 for housing various operating mechanisms. For steam, soleplate 10 has a steam generator cavity or boiler 24 through which, under control of button 26 and spring biased rod 28 of a water valve generally indicated at 29, water may be dropped from tank 20 onto the hot soleplate, the resulting steam being distributed through passages 30 under cover 32 and out ports 12 onto the fabric being ironed. An additional spray attachment, either manual or power operated and forming no part of the present invention, may be operated by control button 34. A typical power spray iron is shown in U.S. Patent 3,041,757 of common assignment. Temperature control 36 operates to thermostatically control the heat generated in the soleplate in a known manner. In order to supply water to the tank 20 for steam, fill opening 38 is provided with direct communication to the tank. Depending on the particular design of the iron, the fill opening and control knobs may be in various locations. Steam irons of the type described preferably use distilled Water for best operation because of the purity of such water. Use of the irons with such water obviates problems of clogging with flakes from mineral deposits in the water and, with proper structure, the water drips at a regular rate and generates steam.

One of the problems in the fine passages and metering orifice of the water valve is making the water flow, and making it flow regularly and immediately on activation of the steam button 26. To this end, it is necessary to provide a wettable surface in order to wick or assist the water through the orifice of the water valve. The invention discloses an improved simplified and inexpensive wicking structure in such a combination.

Referring next to FIG. 2, a means to direct water from the water tank 20 to the boiler 24 is provided in the form of a tubular duct generally indicated at 40, that has an enlarged upper portion 42 and a reduced diameter lower portion 44. Duct 40 is thus preferably cylindrical but is not limited to a cylindrical construction. The duct may be connected to the bottom of tank 20 directly or in a domed portion by an suitable means such as crimping the duct directly into the tank bottom as shown. In order to collect the water and direct it to the metering orifice, a downwardly directed conical orifice member 46 is disposed generally in the upper duct portion in any suitable manner but preferably as a separate member disposed in the duct as shown. For metering the water flow, orifice 48 is provided at the lower apex of the cone and this orifice is periodically cleared by a clean-out pin 50 on the bottom of rod 28 which also seals the orifice in its down or steam-01f position. When rod 28 is withdrawn from the orifice to drip water through to boiler 24, it is necessary to provide a wicking action in order to break the surface tension of the droplets and permit them to flow at a regular rate through lower duct portion 44. Normally, water passing through orifice 48 will not readily form a drop but will tend to run up the outside of the cone due to surface tension. Unless it bridges over to the duct no dripping will occur. Because of surface tension of the drops as well as the small head of water in tank 20 a wet surface is needed to wick or spread the water. Lack of such a surface results in failure of the water to drip into the boiler 24. In order to ensure that the water reaches boiler 24, a separate wicking means 52, preferably in the form of a flat washer, is provided to extend radially from the orifice to the duct to provide a short and direct path wettable surface between the two whereby the water through the orifice is spread along the wicking means to the duct to form droplets which then drip through to the soleplate for generation of steam. The parts described may conveniently be formed of inexpensive and easy to assemble sheet metal parts and wicking means 52 may be nothing more than a flat disk-like washer with a central aperture 54 closely surrounding orifice 48. While wicking means 52 is shown flat, it may be slightly dished but a simple flat washer is preferred since it is less expensive, provides the shortest path, and performs the function. Primarily, a separate wicking means must be provided to break the surface tension and extend radially from the orifice for the shortest path wet surface to the duct lower portion as shown. Preferably, wicking means 52 is disposed at right angles to the direction of water flow through the orifice as shown in FIG. 2, although, as stated above, a slight dish may be formed in means 52 and still perform the wicking function and still be substantially at right angles.

The rate of steam generation in irons of the type shown vary in a range from .012 to .030 pound of steam per minute and the parameters that control this are the orifice size which controls the mass rate of flow and the duct 44 diameter below the orifice which controls the drop rate. These steam rates require a duct 44 diameter in the range of .125 to .219 inch regardless of the size of upper portion 42. If the duct diameter is below this range or too small, it throttles the flow and surface tension holds the drop and the flow stops. On the other hand, if the duct diameter. lower portion is too large, there is too slow a'rate of flow or drop formation that is known as puffing where no continuous or smooth rate of steam is generated. These figures generally hold for all steam irons with or without the wicking structure and all parts are thus designed in a predetermined relation to meet these parameters for proper regular steam generation.

In order for the water to wick simply from the orifice to the duct, wicking means 52 is disposed substantially in the same plane as the orifice 48 in the top of lower portion 44 for the shortest direct-path wettable surface to form drops in portion 44 thereby simplifying the as sembly and manufacture of the parts. Thus, such limitation with the others relating to steam rates is what is intended as the predetermined relation noted in the claims. It should be observed that if the wicking disk means 52 is too high above the orifice shown in FIG. 2, the Water will flow up the cone as though the disk 52 were not present. If tank pressure is sufficient and the water rises sufficiently to the high position of disk 52, it will spread to duct wall 42 and then drip into the steam boiler but is subject to delay because of its long path of travel. If, however, the water does not reach the disk 52 because of low pressure, it stops and surface tension closes orifice 48. On the other hand, if disk 52 is too low below orifice 48, the water tends to Wick or spread out on top of the disk and will not pass through the disk as a drop because of surface tension so again operation is completely stopped. Thus, between these operable and easily determined limits, the disk 52 is substantially in the same plane as orifice 48 and the top of lower portion 44. While portion 44 is shown necked at the change of diameter, it is merely a manufacturing expedient for easy transition to a smaller diameter.

Thus, it will be seen that the simple inexpensive structure shown in FIG. 2 may be preferably made of sheet metal parts, easily assembled, that requires only a separate wicking means preferably in the form of a simple apertured disk with the orifice and the top of the lower duct portion all substantially in the same plane and the disk extending between the orifice and duct wall. This then promotes the proper drippage into the boiler to insure constant and immediate steam flow in the iron.

While there has been shown a preferred form of the invention, obvious equivalent variations are possible in light of the above teachings.

I claim: 1. In a steam iron having an enclosed water tank with a fill opening thereto and a heated soleplate, an on-ofi? water valve and wicking structure controlling water flow from said tank to the soleplate comprising,

a tubular duct connected to direct water from said tank to the soleplate, conical means in said duct having an orifice at the apex thereof, valve means disposed to open and close the orifice,

and separate wicking means connecting the orifice and duct in predetermined relation therewith and,

said wicking means providing a wettable surface between said orifice and duce, whereby water drops passing through the orifice are directed along the wicking means to the duct and then to the soleplate. 2. Apparatus as described in claim 1 where the tubular duct has a lower portion of reduced size,

said orifice and wicking means being disposed substantially at the top of said lower portion. 3, Apparatus as described in claim 2 wherein said wickangles to the direction of water flow through the orifice.

4. Apparatus as described in claim 3 wherein the wicking means has an aperture surrounding said orifice and is disposed substantially in the plane of the orifice.

5. In a steam iron having an enclosed water tank with a fill opening thereto and a heated soleplate, an on-off water valve structure operable to start and stop the flow of water from said tank to the soleplate to generate steam comprising,

a cylindrical duct with an enlarged upper portion and a reduced diameter lower portion connected to direct water from the tank to the soleplate,

a conical orifice member disposed within said upper portion and having an orifice at the lower apex thereof,

valve means disposed to open and close the orifice, and

a separate wicking means extending radially from said orifice to the duct in predetermined relation therewith and with said orifice and duct,

said wicking means providing a wettable surface between said orifice and duct,

whereby water drops through the orifice are directed along the wicking means to the duct and then to the soleplate.

6. Apparatus as described in claim 5 wherein said wicking means is a disk shaped washer plate having an aperture closely surrounding said orifice.

7. Apparatus as described in claim 6 wherein said Washer plate is disposed substantially at right angles to the direction of water flow through the orifice.

8. Apparatus as described in claim 7 wherein the Washer plate, orifice, and top of the lower portion are disposed substantially in the same plane.

References Cited UNITED STATES PATENTS 2,353,426 7/1944 Morton 38-77 2,887,799 5/1959 Kuhn et a1. 38-77 3,188,757 6/1965 Denton 38-77 PATRICK D. LAWSON, Primary Examiner 

